Water-dispersible pressure-sensitive adhesive and tape made therewith

ABSTRACT

Repulpable splicing tape, especially adapted for splicing carbonless paper. The preferred adhesive is a blend of acrylate:acrylic acid copolymer, NaOH and/or LiOH KOH, and certain ethoxylated plasticizing components. A small amount of polyamide-epichlorohydrin crosslinker may also be included.

CROSS-REFERENCE TO RELATED CASE

This application is a continuation-in-part of application Ser. No.529,565, filed Sept. 6, 1983, now abandoned.

BACKGROUND OF THE INVENTION

This invention relates to water-dispersible pressure-sensitive adhesivesand to normally tacky and pressure-sensitive adhesive tapes madetherewith.

Papermaking and printing operations require splicing the end of one rollof paper to the beginning of another, as well as splicing together aroll after defective material is cut out. It is important that suchsplices be made quickly and easily, necessitating the use of an adhesivethat rapidly attains maximum strength and retains it throughoutsubsequent operations. In an era where ecology and conservation are bothvital concerns, it is important that the spliced portions not bedestroyed but that they be returned to the paper mill for reprocessing;it is thus essential that the splices (particularly the adhesive whichis used to make them) be water-dispersible and repulpable. Thiscombination of requirements precludes the use of such conventionaladhesives as normally tacky and pressure-sensitive rubber-resinadhesives. In the past, several water-soluble, pressure-sensitiveadhesives have been devised and employed commercially, but none has beenable to achieve the desired combination of physical properties and lowcost.

An early adhesive used in splicing paper was polyacrylic acid, awater-soluble polymer which is rubbery in the presence of water butwhich becomes brittle and friable at low humidities. Sohl U.S. Pat. No.2,838,421 discloses a splicing tape in which related rubbery polymeradhesives are blended with polypropylene glycol to impart flexibility,particularly in low humidity environments. Double-coated paper tapesmade with such adhesives have been widely used in the papermaking andprinting industry; although excellent in many respects, the release fromthe linear interleaved in the roll of tape is adversely influenced byhigh ambient humidity.

Peterson U.S. Pat. No. 3,441,430 discloses a splicing tape product inwhich the pressure-sensitive adhesive is a water-soluble acrylicacid:ether acrylate copolymer tackified with a liquid water-solubleplasticizer containing at least one ether linkage. Because of the etherlinkage, this adhesive is inherently sensitive to oxidation, and itsperformance characteristics are greatly influenced by conditions towhich it has previously been subjected. For example, exposure to hightemperature (either before or after use in splicing) tends to reducetackiness, flexibility, and repulpability. It is not always possible toprotect the tape from such conditions.

Olson U.S. Pat. No. 3,661,874 discloses a water-solublepressure-sensitive adhesive made by reacting an epoxidized rubberypolymer with a water-soluble secondary monoamine and tackifying thepolymer with a water-soluble tackifier-plasticizer. When carefullyformulated, this adhesive has outstanding physical characteristics,meeting all the requirements imposed by the papermaking industry, butthe manufacturing process is complex and hence expensive.

Blake U.S. Pat. No. 3,865,770 discloses a water-dispersiblepressure-sensitive adhesive in which an acrylate:vinyl carboxylic acidcopolymer is reacted with a lower secondary or tertiary alkanolamine toimpart water solubility, tackifiers (e.g., rosin) or plasticizers (oily,water-soluble polyoxyethylene compounds) being added if necessary.Adhesives of this type have excellent tackiness and heat stability, arereadily repulpable, and are comparatively inexpensive. Special problemsarise, however, when adhesives of this type are used to splicecarbonless paper, the alkanolamine tending to volatilize and migrate,defeating the effectiveness of carbonless paper to perform its intendedfunction, either by forming a stable complex with nickel ion which wouldotherwise react with a dithiooxamide derivative or by neutralizing theacidic substance which would otherwise impart color to an acid-activateddye.

Blake copending U.S. patent application Ser. No. 390,638, filed June 21,1982 (now U.S. Pat. No. 4,413,080), discloses a water-dispersiblepressure-sensitive adhesive intended for use in splicing carbonlesspapers. This adhesive is a blended reaction product of acrylate, acidicrosin or rosin derivative, potassium hydroxide, sodium and/or lithiumhydroxide, and an oily plasticizing water-soluble polyoxyethylenecompound. Although effective in many circumstances, upon exposure toelevated temperatures, the plasticizer may separate and migrate intolayers of paper adjacent the splice, causing transparentization anddecreased adhesion. In addition, some of the NaOH present may migratewith the plasticizer desensitizing to some extent, the color-changingability of the carbonless paper.

SUMMARY OF THE INVENTION

The present invention provides a water-dispersible normally tacky andpressure-sensitive adhesive having all the advantages of the adhesive ofaforementioned U.S. Pat. No. 4,413,080, together with the additionaladvantage that it can be used to splice carbonless paper withoutadversely affecting its performance. Substantially no adhesiveseparation occurs, even in the presence of high temperatures, pressures,and humidities.

The adhesive of the invention comprises the blended reaction product of

(a) 100 parts by weight of a copolymer of monomers consistingessentially of

(1) about 60-85 weight percent of at least one monomeric acrylic acidester of nontertiary alkyl alcohol having 4-14 carbon atoms and

(2) correspondingly about 40-15 weight percent of vinyl carboxylic acid,

(b) about 50 to 250 parts by weight of ethoxylated plasticizingcomponents, sufficient to impart adhesion values such as to cause theadhesive to delaminate kraft paper when tested as described herein,consisting essentially of at least one of the following:

(1) up to about 125 parts by weight, but not so much as to causeadhesive separation, of one or more OH-functional ethoxylatedplasticizers and

(2) one or more electrolyte-tolerant complex acidic esters of phosphoricacid and an ethoxylated nonionic surfactant, and

(c) alkaline hydroxide consisting essentially of

(1) sodium hydroxide, lithium hydroxide, or both sodium and lithiumhydroxide in an amount sufficient to enhance shear strength and minimizebleeding but insufficient to cause separation of any OH-functionalethoxylated plasticizer present, not exceeding about 0.07 hydroxylequivalent if OH-functional ethoxylated plasticizer is the onlyplasticizing component present, and

(2) potassium hydroxide in an amount sufficient to promote watersolubility.

Preferably, tackifying rosin or rosin derivative (especially 75-150parts by weight) is incorporated in the adhesive to promotecompatibility of the ethoxylated plasticizers with the other adhesivecomponents and to enhance adhesion to paper. Presently preferredembodiments of the invention also incorporate both OH-functionalethoxylated plasticizer and phosphoric acid ester, about 50-100 parts byweight of each proving highly satisfactory. In these embodiments, thetotal amount of sodium hydroxide and lithium hydroxide provides fromabout 0.02 to about 0.2 hydroxyl equivalent, and the potassium hydroxideprovides from about 0.1 to about 0.6 hydroxyl equivalent.

Expressed in a somewhat different manner, another preferred embodimentof the invention comprises the just described adhesive wherein theblended reaction product consists essentially of

(a) 100 parts by weight of a copolymer of monomers consistingessentially of

(1) about 60-85 weight percent of at least one monomeric acrylic acidester of nontertiary alkyl alcohol having 4-14 carbon atoms and

(2) correspondingly about 40-15 weight percent of vinyl carboxylic acid,

(b) about 100 to 250 parts by weight of plasticizing components, ofwhich

(1) at least about 50 parts by weight are one or more acidic esters ofphosphoric acid and ethoxylated alcohol or phenol derivative and

(2) the balance is made up of one or more ethoxylated diamines, and

(c) sufficient sodium hydroxide to neutralize at least about 20% of thecopolymer acid function.

The phosphoric acid ester is far more electrolyte-tolerant than theOH-functional polyoxethylene plasticizers, which were described inaforementioned U.S. Pat. No. 4,413,080. As a result, these esters do notseparate from the adhesive composition, even when present in largequantities, when the NaOH content is high, or when the adhesive isexposed to high temperatures, pressures, or humidities. TheOH-functional ethoxylated plasticizers may still be used but must not bepresent in an amount sufficient to cause adhesive separation.

It is considered desirable to include an extremely small amount ofpolyamide-epichlorohydrin crosslinking resin; the presence of thisspecific crosslinking agent greatly improves both firmness andresistance to bleeding. If used in excessive amounts, however, thecrosslinking resin will decrease water solubility and repulpabitity tounacceptably low levels.

As will be apparent from the ranges indicated above, substantialvariations in composition are possible. To illustrate, the use of higherpercentages of short-chain acrylates in a copolymer tends to increasethe hardness of the adhesive, decreasing its tackiness; in such event,it is desirable to use a comparatively higher percentage of plasticizer.On the other hand, high percentages of long chain acrylates increase thetackiness of an adhesive and reduce the need for plasticizers.Similarly, the higher the percentage of vinyl carboxylic acid in thecopolymer, the lower the degree of neutralization necessary to insurewater-solubility. The use of such well-known acrylate monomers isiso-octyl acrylate increases the tackiness of the ultimate adhesive andimproves its adhesion to paper; on the other hand, the resultantcopolymer is harder to dissolve and generally requires the addition ofeither more rosin or more solvent than would otherwise be the case. Ingeneral, if an insufficient amount of rosin is included, ethoxylatedplasticizer (if present) may tend to separate from the ionic neutralizedacrylate polymer, while if too much rosin is included, the tackiness ofthe adhesive is reduced.

It is important to use more than one alkali metal hydroxide inconnection with neutralization, the use of only sodium and/or lithiumhydroxide increasing shear but tending to reduce tackiness of theadhesive to an undesirably low level. On the the other hand,neutralization with only potassium hydroxide increases the tackiness ofthe adhesive but decreases its shear value and increases its bleedingtendency.

Test Procedures

It is believed that a brief explanation of certain test procedures, usedto evaluate various characteristics of water-soluble pressure-sensitiveadhesives and tapes made therewith, will be helpful in understanding theinvention.

Rolling Ball Tack

In this test an 11-mm diameter steel ball is rolled down a plane havinga length of 18 cm and inclined at an angle of 21°30' to a horizontalsurface on which the tape to be evaluated is positioned, adhesive sideup, the adhesive thickness being at least 25 micrometers. The distancethe ball rolls along the horizontal adhesive surface is measured, thetack being inversely proportional to the distance. Further details ofthis test are found in Test Methods for Pressure Sensitive Tapes, 7thEdition, Pressure Sensitive Tape Council, Glenview, Ill. 60025, Test No.PSTC-6. Generally speaking, although not always, adhesives used in thepractice of this invention will have a rolling ball tack value of nomore than 15 cm. Where tape is to be used in splicing rolls of papertogether at speeds of perhaps 1000 m/minute (i.e., in making so-calledflying splices), tack values of less than 5 cm are greatly preferred.

Certain adhesives embodying the invention yield high rolling ball tackvalues (greater than 15 cm), yet adhere aggressively to paper. Theseadhesives, which are usually considered relatively firm, would notfunction well in making flying splices but would function extremely wellin making finished roll splices. The following test, which is useful inevaluating the ability of both tacky and firm adhesives to adhere topaper.

180° Peel Adhesion to Paper

A 3.175 cm strip of kraft paper is laminated to a 5 cm×12.5 cm stainlesssteel test panel using a double-faced pressure-sensitive tape. One endof a 2.54 cm×25 cm strip of sample tape having a 68 g/m² kraft paperbacking is then laid over the laminated kraft paper. Uniform adhesivecontact is assured by quickly (1 second) passing a 2 kg roller over the12.5-cm sample length.

The tape is then doubled back on itself and peeled from the kraft papersurface at 30.5 cm/minute, using a method generally equivalent to thatdescribed in Test PSTC-1 "Test Methods for Pressure Sensitive Tapes",7th Edition, Pressure Sensitive Tape Council, Glenview, Ill., 60025. Ifthe tape adheres well to the kraft paper, the numerical result may beunimportant, as it may reflect only the force necessary to delaminatethe paper surface. In such a case, delamination should be the reportedresult. Preferred adhesives will cause delamination.

Shear Adhesion

A 2.54-cm×2.54-cm end portion of a 2.54-cm×15-cm strip of tape, formedby coating a 25-micrometer thick layer of adhesive on 68 g/m²supercalendered kraft paper backing, is adhered to a bright annealedsteel test panel and rolled down with two passes of a 2-kg roller. Thepanel is then clamped in a jig which is disposed at 2°to the vertical,so that the 12.5-cm free end of the tape extends downward, at an angleof 178° to the test panel, and a 1000-gram weight is attached to thetape end. The time for the tape to separate from the panel is reportedin to the nearest minute, the shear strength being directly related tothe elapsed time. Further details are found in the aforementioned TestMethods for Pressure-Sensitive Tapes, Test PSTC-7. For tapes made withadhesive of this invention, it is desirable to have shear time as highas possible, preferably exceeding 100 minutes, although an extremelytacky adhesive may be satisfactory if its shear time is as low as 40minutes.

Repulpability

A 20-cm×2.54-cm strip of double-coated splicing tape is sandwichedbetween two 20-cm×2.54-cm strips of blotter paper* and cut intoapproximately 1.5-cm squares. To these squares are added a sufficientnumber of 1.5-cm squares of blotter pater to make a total of 15 grams,after which all the squares are placed in a Waring Blendor with 500 mlof water. After the blendor has run for 20 seconds, the stock that hassplattered up the sides and onto the cover is washed back into thebottom with a water bottle. The blendor is again run for 20 seconds,washed as before, and run for a final 20 seconds. The stock is thenremoved from the blendor, rinsed twice with water, and made into a handsheet, using a large sheet mold. The sheet is couched off the mold,pressed between blotters for 11/2 minutes in a hydraulic press, removed,dried, and examined for any particles of unrepulped splicing tape. If nosuch particles are present, the tape is considered satisfactory. Furtherdetails are found in TAPPI Test UM-213.

The foregoing test does not apply to tape products where, e.g., thebacking is a polyester film, which does not lend itself to repulping.Such backings are strong, however, and may be used in splicing tape,provided the loosened backing is mechanically removed from the beater.

The rolling ball tack test and repulpability test are equally applicableto transfer tapes, where the adhesive layer, (or, optionally two layersof adhesive flanking a fibrous reinforcing layer) is carried by astrippable release liner. In using such tapes, the exposed surface ofthe adhesive is placed in contact with a first sheet of paper, the linerstripped away, and a second sheet of paper adhered to the newly exposedadhesive surface.

Plasticizer Separation and Carbonless Paper Deactivation

Since carbonless papers function by the interaction of chemicalmaterials on two separate paper surfaces, samples for this test must beprepared using both of the papers involved. A 2.54-cm strip of thesubject tape is adhered to the side of the paper opposite the coatedside to be evaluated and the resulting laminate placed in a 65° C. ovenfor 24 hours, after which the paper is examined for plasticizerseparation and absorption into the paper, as evidenced bytransparentization. Each of the taped samples is then paired with afresh sheet of the complementary paper. The paired sheets are placed ina typewriter and a message is typed over the area where the tape hasbeen in contact with the paper. Any abnormality in the development ofthe carbonless image is noted.

Bleeding Tendency

This test qualitatively measures the tendency of an adhesive to bleedthrough a paper sheet when subjected to pressure and/or elevatedtemperatures. Strips of double-faced tape, both adhesive coatings beingon the type to be evaluated, are placed between two sheets of the paperchosen, after which several additional sheets of the paper are laid oneach side of the sandwich formed. The resultant sample is placed in aplaten press for 15 hours at about 10 kg/cm² pressure and 40° C. andsubsequently examined. Bleeding is deemed "slight" and the adhesive isconsidered acceptable if it bleeds no more than slightly into the firstsheet and does not adhere to the second sheet. If it bleeds through thefirst sheet and adheres only lightly to the second (i.e., blocks), it isconsidered less desirable but may be acceptable. Unsatisfactoryadhesives adhere tightly to, and possibly bleed through, a second sheet,a condition designated "severe". Results obtained in this test will, ofcourse, vary with the specific paper used and the ambient humidity andtemperature, but comparisons of tapes run within the same set canusually be made with validity.

DESCRIPTION OF PRESENTLY PREFERRED EMBODIMENTS

It is believed that understanding of the invention will be enhanced byconsidering several illustrative but non-limiting examples. In eachcase, an acrylate:vinyl carboxylic acid copolymer was prepared,generally as described in Ulrich U. S. Pat. No. Re. 24,906. The monomersto be copolymerized were dissolved in ethyl acetate and, usingazobisisobutyronitrile as a catalyst, the solution held at 53° C. for 24hours, at which time polymerization was largely completed. To theresultant viscous solution was then added sufficient methanol to reducethe solids content to about 20-22%.

A separate composition was prepared by mixing phosphoric acid esterand/or OH-functional ethoxylated plasticizer, methanol, water, andalkali metal hydroxides. When rosin or rosin derivatives are used, theyare introduced into this composition. Mixing time is increased whensolid rosin is present. The final mixture is a clear, colorless toamber, low viscosity solution. Appropriate amounts of the compositionwere blended into the acrylate:vinyl carboxylic acid copolymer, yieldinga clear, substantially colorless to amber solution. This solution wascoated directly on a 68 g/m² supercalendered kraft paper backing and thesolvent evaporated to leave a layer of normally tacky andpressure-sensitive adhesive on the order of 25 micrometers thick. Theresultant tape product was then evaluated, using the previouslydescribed test procedures.

For convenience, the examples are set forth below in tabular form, allprepared substantially in accordance with the procedure just described,parts and percentages being by weight unless otherwise noted. The effectof varying the types, ratios, and amounts of various components will bereadily apparent from examining the reported data. In many instances,adhesives which perform unsatisfactorily are capable of readymodification to improve their performance significantly. The followingabbreviations have been employed:

    ______________________________________                                        Acrylate monomers                                                             BA           butyl acrylate                                                   IOA          iso-octyl acrylate                                               Vinyl Carboxylic Acid Monomers                                                AA           acrylic acid                                                     Rosins                                                                        TORD         disproportionated tall oil rosin                                 TORP         polymerized tall oil rosin                                       WR           wood rosin                                                       WRH          hydrogenated wood rosin                                          WRP          polymerized wood rosin                                           Phosphoric Acid Esters                                                        PE-510       clear to slightly hazy, viscous                                               liquid having an aromatic                                                     hydrophobic base, a density of                                                1.08-1.09, and an acid number (mg                                             KOH/g product) to first                                                       inflection point (pH 5.5) of                                                  49-59, available from GAF                                                     Corporation under the registered                                              trademark "Gafac" PE-510                                         RE-610       Slightly hazy, viscous liquid                                                 having an aromatic hydrophobic                                                base, a density of 1.10-1.12, and                                             an acid number of 62-72,                                                      available from GAF Corporation as                                             "Gafac" RE-610                                                   RS-610       Hazy, viscous liquid having an                                                aliphatic hydrophobic base, a                                                 density of 1.04-1.06, and an acid                                             number of 75-85, available from                                               GAF Corporation as "Gafac"                                                    RS-610.                                                          OH-Functional Ethoxylated Plasticizers                                        T/13         PEG-3 tallow aminopropylamine,                                                available from Armak under the                                                registered trademark                                                          "Ethoduomeen" T/13                                               T/20         PEG-10 tallow aminopropylamine,                                               available from Armak as                                                       "Ethoduomeen" T/20                                               T/25         PEG-15 tallow aminopropylamine,                                               available from Armak as                                                       "Ethoduomeen" T/25                                               ("PEG" followed by a number refers to moles of                                polyoxyethylene glycol.)                                                      152          Ethoxylated octylphenol having an                                             oxyethylene content of about 52%,                                             available from GAF Corporation                                                under the registered trademark as                                             "Igepal" CA-520                                                  162          Ethoxylated nonylphenol having an                                             oxyethylene content of about 63%,                                             available from GAF Corporation as                                             "Igepal" CO-630                                                  ______________________________________                                    

    __________________________________________________________________________                                METAL HYDROXIDE                                                               NaOH           KOH                                                                   % CO-           % CO-                      COPOLYMER                          POLYMER         POLYMER                        PARTS PARTS                                                                              PARTS COOH   OH     COOH    OH      COOH                       EX. BA    IOA  AA    EQUIV  EQUIV  FUNCTION                                                                              EQUIV   FUNCTION                   __________________________________________________________________________     1  75    --   25    0.347  0.208  60      0.223   64                          2  75    --   25    0.347  0.208  60      0.223   64                          3  75    --   25    0.347  0.208  60      0.223   64                          4  75    --   25    0.347  0.208  60      0.223   64                          5  75    --   25    0.347  0.208  60      0.223   64                          6  75    --   25    0.347  0.278  80      0.223   64                          7  75    --   25    0.347  0.347  100     0.235   68                          8  75    --   25    0.347  0.174  50      0.186   54                          9  75    --   25    0.347  0.139  40      0.186   54                         .[.10                                                                             75    --   25    0.347  0.139  40      0.477   137.].                     11  75    --   25    0.347   0.139**                                                                              40**   0.464   134                        12  75    --   25    0.347  0.139  40      0.471   136                        13  75    --   25    0.347  0.139  40      0.483   139                        14  75    --   25    0.347  0.139  40      0.520   150                        15  75    --   25    0.347  0.139  40      .[.0.186.]..Iadd.0.255.Iaddend.                                               2       73                         16  75    --   25    0.347  0.208  60      0.198   57                         17  75    --   25    0.347  0.208  60      0.198   57                         18  75    --   25    0.347  0.035  10      0.469   135                        19  75    --   25    0.347  0.035  10      0.469   135                        20  75    --   25    0.347  0.035  10      0.469   135                        21  75    --   25    .Iadd.0.347.Iaddend..[.0.208.].                                                      0.104  30      0.321   92                         22  75    --   25    .Iadd.0.347.Iaddend..[.0.208.].                                                      0.104  30      0.321   92                         23  75    --   25    .Iadd.0.347.Iaddend..[.0.208.].                                                      0.052  15      0.607   175                        24  75    --   25    .Iadd.0.347.Iaddend..[.0.208.].                                                      0.035  10      0.296   83                         25  75    --   25    .Iadd.0.347.Iaddend..[.0.208.].                                                      0.035  10      0.321   92                         26  75    --   25    .Iadd.0.347.Iaddend..[.0.208.].                                                       0.035**                                                                               10**  0.246   71                         27  75    --   25    .Iadd.0.347.Iaddend..[.0.208.].                                                      0.035  10      0.322   93                         .[.28                                                                             75    --   25    0.208  0.035  10      0.357   103.].                     29  75    --   25    .Iadd.0.347.Iaddend..[.0.208.].                                                      0.035  10      0.383   110                        .[.30                                                                             75    --   25    0.208  0.035  10      0.383   110.].                     .[.31                                                                             75    --   25    0.208  0.035  10      0.401   116.].                     .[.32                                                                             75    --   25    0.208  0.035  10      0.248   71.].                      33  75    --   25    .Iadd.0.347.Iaddend..[.0.208.].                                                      0.017   5      0.376   108                        34  75    --   25    .Iadd.0.347.Iaddend..[.0.208.].                                                      0.017   5      0.401   116                        .[.35                                                                             75    --   25    0.208  --     --      --      --.].                      36  75    --   25    0.347  0.069  20      0.186   54                         37  75    --   25    0.347  --     --      0.394   114                        38  75    --   25    0.347  0.208  60      0.149   43                         .[.39                                                                             75    --   25    0.347  0.208  60      0.149   43.].                      40  75    --   25    0.347  0.208  60      0.074   21                         .[.41                                                                             75    --   25    0.347  0.208  60      0.074   21.].                      42  75    --   25    0.347  0.208  60      --      --                         .[.43                                                                             75    --   25    0.347  0.208  60      --      --.].                      44  75    --   25    0.347  0.208  60      0.273   79                         45  75    --   25    0.347  0.208  60      0.322   93                         46  75    --   25    0.347  0.416  120     --      --                         47  75    --   25    0.347  0.364  105     --      --                         48  75    --   25    0.347  0.139  40      0.124   36                         .[.49                                                                             75    --   25    0.347  0.139  40      0.124   36.].                      50  75    --   25    0.347  0.139  40      0.099   29                         51  75    --   25    0.347  0.139  40      0.074   21                         52  75    --   25    0.347  0.139  40      0.052   15                         53  75    --   25    0.347  0.139  40      0.124   36                         54  75    --   25    0.347  0.139  40      0.124   36                         55  75    --   25    0.347  0.139  40      0.124   36                         56  75    --   25    0.347  0.139  40      0.124   36                         57  75    --   25    0.347  0.139  40      0.124   36                         58  75    --   25    0.347  0.139  40      0.124   36                         59  75    --   25    0.347  0.139  40      0.124   36                         60  75    --   25    0.347  0.139  40      0.124   36                         61  75    --   25    0.347  0.174  50      0.198   57                         62  75    --   25    0.347  0.174  50      0.198   57                         63  75    --   25    0.347  0.174  50      0.198   57                         64  75    --   25    0.347  0.139  40      0.198   57                         65  75    --   25    0.347  0.139  40      .Iadd.0.396.Iaddend..[.0.296.].                                                       114                        66  75    --   25    0.347  0.139  40      0.434   125                        67  75    --   25    0.347  0.208  60      0.356   103                        68  75    --   25    0.347  0.208  60      0.489   141                        69  75    --   25    0.347  0.208  60      0.623   179                        70  85    --   15    0.208  0.208  100     0.174   84                         71  80    --   20    0.278  0.208  75      0.174   63                         72  80    --   20    0.278  0.208  75      0.198   71                         73  70    --   30    0.416  0.208  50      0.223   54                         74  65    --   35    0.486  0.208  43      0.23    46                         75  60    --   40    0.555  0.208  39      0.223   40                         76  45    30   25    0.347  0.208  60      0.223   64                         77  64    16   20    0.278  0.028  75      0.174   .Iadd.63.Iaddend..[.64.                                                       ].                         78  64    16   20    0.278  0.028  75      0.198   78                         .[.79                                                                             64    16   20    0.278  0.174  62      0.421   151.].                     80  64    16   20    0.278  0.174  62      0.421   151                        81  64    16   20    0.278  0.174  62      0.446   .Iadd.160.Iaddend..[.12                                                       6.].                       82  64    16   20    0.278  0.174  62      0.421   151                        83  64    16   20    0.278  0.174  63      0.198   71                         __________________________________________________________________________                                         %                                                                             POLY-                                    PLASTICIZERS                         AMIDE:                                                  OH-                   EPI-  ROLL-                                             FUNCTIONAL                                                                             ROSIN        CHLORO                                                                              ING  SHEAR                                                                              BLEED-                                  ETHOXY-  OR ROSIN     HYDRIN                                                                              BALL ADHE-                                                                              ING                      H.sub.3 PO.sub.4                                                                        ESTER                                                                              LATED    DERIVATIVE   CROSS-                                                                              TACK,                                                                              SION,                                                                              TEN-                         TYPE  PARTS                                                                              TYPE                                                                              PARTS                                                                              TYPE    PARTS                                                                              LINKER                                                                              CM   MIN. DENCY                    __________________________________________________________________________     1  PE-510                                                                              231  --  --   --      --   --    .[.2.9.].                                                                          38   NONE                      2  PE-510                                                                              231  --  --   --      --   0.031 1.9  67   NONE                      3  PE-510                                                                              231  --  --   --      --   0.062 1.9  117  NONE                      4  PE-510                                                                              231  --  --   --      --   0.093 2.2  205  NONE                      5  PE-510                                                                              231  --  --   --      --   0.125 1.9  215  NONE                      6  PE-510                                                                              238  --  --   --      --   0.125 2.5  65   NONE                      7  PE-510                                                                              243  --  --   --      --   --    1.6  88   NONE                      8  PE-510                                                                              191  --  --   --      --   --    2.5  48   NONE                      9  PE-510                                                                              191  --  --   --      --   --    2.9  38   SL                       .[.10                                                                             PE-510                                                                              80   T/20                                                                              --   WRH     136  --    5.5  186  --.].                    11  PE-510                                                                               75  163 79   WRH     136  --    17.0 296  --                       12  PE-510                                                                               75  163 79   WRH     136  --    10.4 211  --                       13  PE-510                                                                               80  163 74   WRH     136  --    4.1  320  --                       14  PE-510                                                                              126  163 53   WRH     136  --    5.6  111  --                       15  PE-510                                                                              191  --  --   --      --   --    2.5  48   NONE                     16  PE-510                                                                              203  --  --   --      --   --    3.2  60   NONE                     17  PE-510                                                                              203  --  --   --      --   0.125 2.9  290  NONE                     18  PE-510                                                                               95  163 75   WRH     86   0.375 2.8  1270 --                       19  PE-510                                                                               95  163 75   WRH     86   0.50  2.2  1136 --                       20  PE-510                                                                               95  163 75   WRH     86   0.625 3.7  965  --                       21  PE-510                                                                               71  163 50   WRH     86   --    .[.2.0.].                                                                          .[.517.].                                                                          --                       22  PE-510                                                                               71  163 75   WRH     86   --    9.6  230  --                       23  PE-510                                                                              172  T/20                                                                              50   WRH     92   0.125 2.1  70   --                       24  PE-510                                                                               47  163 75   WRH     86   --    .[.65+.].                                                                          .[.519+.].                                                                         --                       25  PE-510                                                                               71  163 50   WRH     86   --    15+  .[.584+.].                                                                         --                       26  --    --   163 125  WRH     86   --    12.0 338  --                       27  PE-510                                                                               71  163 75   WRH     86   --    8.5  177  --                       .[.28                                                                             PE-510                                                                              48   163 75   WRH     86   --    8.3  1417 --.].                    29  PE-510                                                                               71  163 50   WRH     86   0.094 10.0 1036 --                       .[.30                                                                             PE-510                                                                              71   163 75   WRH     86   0.094 4.7  890  --.].                    .[.31                                                                             PE-510                                                                              95   163 75   WRH     86   0.125 3.3  625  --.].                    .[.32                                                                             --    --   163 125  WRH     86   0.156 8.1  799  --.].                    33  PE-510                                                                               48  163 75   WRH     86   --    10.8 340  --                       34  PE-510                                                                               71  163 50   WRH     86   --    16.7 329  --                       .[.35                                                                             PE-510                                                                              80   T/25                                                                              74   --      --   --    8.3  250  --.].                    36  PE-510                                                                              191  --  --   --      --   --    6.0  23   MOD.                     37  PE-510                                                                              191  --  --   --      --   --    .[.2.9.].                                                                          34   SEV.                     38  PE-510                                                                              231  --  --   --      --   --    1.9  24   --                       .[.39                                                                             PE-510                                                                              231  --  --   --      --   --    2.2  237  --.].                    40  PE-510                                                                              231  --  --   --      --   --    1.6  18   --                       .[.41                                                                             PE-510                                                                              231  --  --   --      --   --    1.9  197  --.].                    42  PE-510                                                                              231  --  --   --      --   --    1.3  11   --                       .[.43                                                                             PE-510                                                                              231  --  --   --      --   --    1.9  40   --.].                    44  RE-610                                                                              228  --  --   --      --   --    3.2  16   --                       45  RS-610                                                                              226  --  --   --      --   --    4.8  17   --                       46  PE-510                                                                              235  --  --   --      --   --    4.4  75   --                       47  PE-510                                                                              235  --  --   --      --   --    3.8  26   --                       48  PE-510                                                                              125  T/20                                                                              83   WRH     75   --    .[.2.5.].                                                                          .[.36.].                                                                           --                       .[.49                                                                             PE-510                                                                              125  T/20                                                                              83   WRH     75   --    3.5  165  --.].                    50  PE-510                                                                              100  T/20                                                                              83   WRH     75   --    2.9  77   --                       51  PE-510                                                                               75  T/20                                                                              83   WRH     75   --    3.2  307  --                       52  PE-510                                                                               50  T/20                                                                              83   WRH     75   --    10.2 1562 --                       53  PE-510                                                                              125  T/25                                                                              83   WRH     75   --    2.2  67   --                       54  PE-510                                                                              125  T/20                                                                              55   WRH     50   --    3.8  75   --                       55  PE-510                                                                              125  T/20                                                                              28   WRH     25   --    5.1  63   --                       56  PE-510                                                                              125  T/20                                                                              83   TORP    75   --    4.8  100  --                       57  PE-510                                                                              125  T/20                                                                              83   WRP     75   --    4.8  81   --                       58  PE-510                                                                              125  T/20                                                                              83   TORD    75   --    2.2  64   --                       59  PE-510                                                                              125  T/20                                                                              83   WR      75   --    3.8  63   --                       60  PE-510                                                                              126  T/13                                                                              83   .Iadd.WRH.Iaddend..[.WRD.].                                                           75   --    3.8  86   --                       61  PE-510                                                                              203  T/20                                                                              27   WRH     13   --    3.8  36   --                       62  PE-510                                                                              203  T/20                                                                              27   --      --   --    .[.1.9.].                                                                          29   --                       63  PE-510                                                                              203  T/20                                                                              54   --      --   --    1.6  24   --                       64  RE-610                                                                              211  --  --   WRH     68   --    4.1  29   --                       65  PE-510                                                                              200  --  --   WRH     68   --    3.2  .[.29.].                                                                           --                       66  RE-610                                                                              198  --  --   WRH     68   --    3.2  34   --                       67  PE-510                                                                              179  --  --   WRH     47   --    7.9  114  --                       68  PE-510                                                                              179  --  --   WRH     94   --    3.0  .[.100.].                                                                          --                       69  PE-510                                                                              179  --  --   WRH     140  --    2.5  125  --                       70  PE-510                                                                              180  --  --   --      --   --    7.0  19   --                       71  PE-510                                                                              180  --  --   --      --   --    3.2  39   --                       72  PE-510                                                                              205  --  --   --      --   --    1.6  10   --                       73  PE-510                                                                              231  --  --   --      --   --    3.2  49   --                       74  PE-510                                                                              231  --  --   --      --   --    5.1  42   --                       75  PE-510                                                                              231  --  --   --      --   --    8.6  61   --                       76  PE-510                                                                              231  --  --   --      --   --    3.2  16   --                       77  PE-510                                                                              180  --  --   --      --   --    2.9  31   --                       78  PE-510                                                                              205  --  --   --      --   --    1.3  31   --                       .[.79                                                                             PE-510                                                                              25   163 74   WRH     138  --    6.8  178  --.].                    80  PE-510                                                                               26  163 107  WRH     138  --    3.1  112  --                       81  PE-510                                                                               51  163 107  WRH     138  --    2.7  54   --                       82  PE-510                                                                               26  152 134  WRH     138  --    3.1  .[.164.].                                                                          --                       83  PE-510                                                                              203  T/20                                                                              27   --      --   --    1.3  34   --                       __________________________________________________________________________      *based on total adhesive solids                                              **LiOH used instead of NaOH                                              

Those persons skilled in the art will recognize that it is not feasibleto set forth all the variations to which this invention is susceptible,and many modifications will readily suggest themselves, especially ifcertain principles are borne in mind. For example, the shorter the chainlength of the alcohol from which the acrylate monomer is derived, thefirmer the resultant pressure-sensitive adhesive. If a softer adhesiveis desired, the chain length of the alcohol may be increased. If greatershear strength for an adhesive made with a given copolymer is desired, ahigher molecular weight, as evidenced by a higher inherent viscosity,can be used; alternatively, a small amount of a crosslinking agent canbe incorporated if repulpability is not compromised in the finaladhesive.

Other monomers such as fumarates may be incorporated to provide sidechain attachments to the polymer backbone through pendent ester linkagesin the same manner as acrylate esters.

It will likewise be recognized that, to achieve specific results, it maybe desirable to incorporate minor amounts of monomeric modifiers intocopolymers used to formulate adhesives of the invention, for example,styrene or methyl methacrylate increases firmness, tertiary butylstyrene increases tack, etc. Similarly, dyes, pigments, fillers, etc.may be added where necessary or desirable.

Although this information has been particularly described with respectto a splicing tape for papermaking and printing operations, thepressure-sensitive adhesive has many other uses. For example,water-soluble adhesive labels may be applied to dishes, windows, orother surfaces which it is commmon to clean with aqueous solvent. Clothlabels coated with this adhesive may readily be washed from garments towhich they are affixed. Likewise, since the adhesive is substantiallyinsoluble in most oils or similar hydrocarbon solvents, it may beemployed in applications where conventional normally tacky andpressure-sensitive adhesive tapes prove unsatisfactory.

I claim:
 1. Normally tacky and pressure-sensitive water-dispersibleadhesive especially suitable for splicing carbonless paper, comprisingthe blended reaction product of(a) 100 parts by weight of a copolymer ofmonomers consisting essentially of(1) about 60-85 weight percent of atleast one monomeric acrylic acid ester of nontertiary alkyl alcoholhaving 4-14 carbon atoms, and, correspondingly, (2) about 40-15 weightpercent of vinyl carboxylic acid, (b) about 50 to 250 parts by weight ofethoxylated plasticizing components, sufficient to impart adhesionvalues such as to cause the adhesive to delaminate kraft paper whentested as described herein, consisting essentially of at least one ofthe following:(1) up to about 125 parts by weight, but not so much as tocause adhesive separation, of one or more OH-functional ethoxylatedplasticizers and (2) one or more electrolyte-tolerant complex acidicesters of phosphoric acid and an ethoxylated nonionic surfactant, and(c) alkaline hydroxide consisting essentially of(1) sodium hydroxide,lithium hydroxide, or both sodium hydroxide and lithium hydroxide, in anamount sufficient to enhance shear strength and minimize bleeding butinsufficient to cause separation of any OH-functional ethoxylatedplasticizer present, not exceeding about 0.07 hydroxyl equivalent ifOH-functional ethoxylated plasticizer is the only plasticizing componentpresent, and (2) potassium hydroxide in an amount sufficient to promotewater solubility.
 2. The adhesive of claim 1 wherein the total amount ofsodium hydroxide and lithium hydroxide provides from about 0.02 to about0.2 hydroxyl equivalent and the potassium hydroxide provides from about0.1 to about 0.6 hydroxyl equivalent.
 3. The adhesive of claim 1 whereinthe blended reaction product consists essentially of(a) 100 parts byweight of a copolymer of monomers consisting essentially of(1) about60-85 weight percent of at least one monomeric acrylic acid ester ofnontertiary alkyl alcohol having 4-14 carbon atoms, and,correspondingly, (2) about 40-15 weight percent of vinyl carboxylicacid, (b) about 100 to 250 parts by weight of plasticizing components,of which(1) at least about 50 parts by weight are one or more acidicesters of phosphoric acid and ethoxylated alcohol or phenol derivativeand (2) any balance is made up of one or more ethoxylated diamines orethoxylated phenols, and (c) sufficient sodium hydroxide to neutralizeat least about 5% of the copolymer acid function.
 4. The adhesive ofclaim 3 wherein the acrylic acid ester comprises butyl acrylate and thevinyl carboxylic acid comprises acrylic acid.
 5. Normally tacky andpressure-senstive adhesive tape comprising a layer of the adhesive ofclaim 3 coated on a sheet backing.
 6. The tape of claim 5 wherein atackifying rosin or rosin derivative is included in the adhesive.
 7. Thetape of claim 5 wherein an extremely small amount ofpolyamide-epichlorohydrin crosslinking resin is included in theadhesive.
 8. The tape of claim 5 wherein the adhesive consistsessentially of 100 parts of a butyl acrylate: acrylic acid copolymerhaving a COOH equivalent in the approximate range of 0.25 to 0.45,sufficient NaOH to provide approximately 0.02-0.2 OH equivalent,sufficient KOH to provide approximately 0.1-0.6 OH equivalent, about50-250 parts of plasticizer, and 0.08-0.50% by weightpolyamide-epichlorohydrin resin crosslinker based on total adhesivesolids.
 9. The adhesive of claim 1 wherein the plasticizing componentsinclude both OH-functional ethoxylated plasticizer and acidic ester ofphosphoric acid and ethoxylated alcohol or phenol derivative.
 10. Theadhesive of claim 9 wherein about 50 to 100 parts by weight of oilyethoxylated plasticizer are present.
 11. The adhesive of claim 10wherein about 50 to 100 parts by weight of the phosphoric acid ester arepresent.
 12. The adhesive of claim 11 wherein from about 75 to about 150parts by weight of rosin or rosin derivative are present.
 13. Normallytacky and pressure-sensitive adhesive tape comprising a layer of theadhesive of claim 12 coated on a sheet backing.
 14. The tape of claim 13wherein an extremely small amount of polyamide-epichlorohydrin resincrosslinker is included in the adhesive.